Looking Up: Find your way with a star map

Friday

Dec 1, 2017 at 10:48 AMDec 1, 2017 at 10:48 AM

Peter Becker More Content Now

Evening star maps can easily be found in astronomy field books found in public libraries or maybe your own book shelf. You can also search online for them. They will show you the constellations visible for that season or month.

The bright Moon (or excessive light pollution) makes finding many constellations very difficult, although the brighter stars may still be picked out, especially far from the Moon. Full Moon is this Sunday, December 3rd; each night this week and the one following, the Moon rises later and later, providing a longer “window” of darker skies. Find a dark site, away from neighborhood lights.

When using a star map showing the whole sky, pick the direction you wish to face, and hold the map with that direction at the bottom. If you want to face north, turn the map so that north is at bottom.

The star map likely lists the hours to use the map. Since the whole sky keeps turning (as the Earth spins), the view will be completely different at, say, 3 a.m. than at 9 p.m.

To read the star map outside, use a flashlight that is cover over with red paper or red fabric- or uses a red bulb. The dimmer, red light helps to preserve your night vision. Obviously you may need to remove the red covering to use the light to walk outside or back indoors! (You may also use an electronic tablet.)

I like using a “planisphere,” which is a map of the entire night sky you can see throughout the year, on a wide disc or wheel. There is a cover over the star map, with an opening to reveal the sky you can see at any one date or hour of night. Turning the circular star map shows the sky at different dates and hours, which are marked around the edge.

If you have or acquire a telescope, and want to search deeper into the night sky, you will need a star atlas. There are many versions sold, showing stars much fainter than the unaided eye can see, and pointing out star clusters, galaxies, nebulae and other deep sky objects you can find. Rather than an all-sky map, a star atlas shows small close-up sections of the sky, on various pages.

Some of the brighter of these deep sky destinations can be located with only a pair of household binoculars. Your enjoyment of the Heavens can be multiplied many times as you learn to use the star maps and gain experience.

The next clear nightProminent in the northern sky on an early December night is the W-shaped Cassiopeia constellation, which will be high up. The Big Dipper is straight below, skimming the horizon or perhaps obscured. Half way between the front two stars of the Dipper’s “bowl” and Cassiopeia is the North Star.

Looking east, Orion is just rising. Higher up and to the left is the bright yellow star Capella. Over to the right of Capella and well above Orion is the glittering, compact star cluster, the Pleiades.

High up in the southern sky is the large “Great Square” of Pegasus.

In the west, look for the very bright blue-white star Vega. To the upper left is the bright star Deneb, on top the “Northern Cross” figure. To the lower left is the bright star Altair.

Early risers will want to look southeast, about a half hour before sunrise. The bright planet Jupiter is prominent, shining in the coming dawn. Much dimmer is the reddish planet Mars, to the upper right. The bright white star Spica is nearby, to the right of Mars.

Looking a half hour after sunset, very low in the southwest, you may glimpse the planet Mercury, and maybe dimmer Saturn to the lower right (about to be engulfed by the solar glare). Binoculars are advised.Keep looking up!

— Peter Becker is Managing Editor at The News Eagle in Hawley, PA. Notes are welcome at news@neagle.com. Please mention in what newspaper or web site you read this column.